ABSTRACT

1. Broiler breeders are subjected to qualitative or quantitative feed restrictions to prevent obesity, which causes major health and welfare problems. Diluting their feed by adding inert or low nutrient, bulky materials can reduce obesity, but the capacity of the gut needs to be determined to apply this strategy successfully. Two trials were conducted to measure the bulk capacity of Ross 308 broiler breeders prior to and after the onset of lay. The trial was completely randomised, with nine individually-caged breeders, with each cage as a replicate, totalling 189 birds per trial

2. Birds were given ad libitum access to one of 21 maize-soyabean based feeds, an undiluted control or progressive dilution (10, 20, 30 and 40%) with either cellulose fibre, rice husk, sand, vermiculite or sawdust. Feeds were analysed for density, crude-, acid detergent- and neutral detergent-fibre, water-holding capacity (WHC), cation-exchange capacity and oil-holding capacity.

2. In general, feed intake (scaled to body weight^0.67) increased and then declined as the proportion of each diluent increased. Intake increased linearly when rice hulls and sand were used as diluents.

3. Water holding capacity was the most appropriate measure to define the gut capacity of broiler breeders.

4. The trial data was used to estimate the maximum-scaled feed intake (SFI_max) in broiler breeders, which was 240–56.1WHC + 4.34WHC² g/kg^0.67/d.

摘要

1. 肉种鸡受到定性或定量的饲料限制以防止肥胖，这会导致重大的健康和福利问题。通过添加惰性或低营养的大块材料来稀释饲料可以减少肥胖，但需要确定肠道的容量才能成功应用这一策略。进行了两项试验来测量罗斯 308 肉种鸡在产蛋开始之前和之后的散装能力。该试验是完全随机的，有九只单独笼养的种鸡，每个笼子作为复制品，每次试验总共有 189 只鸡

2. 鸟类可以随意获取 21 种基于玉米-大豆的饲料中的一种，未稀释的对照或用纤维素纤维、稻壳、沙子、蛭石或锯末逐步稀释（10%、20%、30% 和 40%）。分析进料的密度、粗纤维、酸性洗涤剂纤维和中性洗涤剂纤维、持水能力 (WHC)、阳离子交换能力和持油能力。

2. 一般来说，随着每种稀释剂比例的增加，采食量（按体重^0.67）先增加后减少。当稻壳和沙子用作稀释剂时，摄入量呈线性增加。

3. 持水能力是确定肉种鸡肠道容量的最合适的指标。

4. 试验数据用于估算肉种鸡的最大规模采食量（SFI _{max ），为240-56.1WHC + 4.34WHC} ² g/kg ^0.67 /d。